Department of Laboratory Medicine, University of Washington, Seattle.
Department of Laboratories, Seattle Children's Hospital, Seattle, WA.
Am J Clin Pathol. 2019 Mar 1;151(4):424-432. doi: 10.1093/ajcp/aqy156.
To determine the relationship between baseline variations in the partial thromboplastin time (PTT) and the discordance between the PTT and anti-Xa heparin activity (anti-Xa) during heparin therapy.
The baseline PTT on heparin was determined using automated heparin neutralization with protamine (prPTT). The prPTT was used to calculate a baseline-corrected PTT on heparin to reduce discordance with anti-Xa measurements.
The prPTT removed up to 1 U/mL of heparin, returning baseline values for normal, factor-deficient, and lupus inhibitor plasmas. A prolonged prPTT was seen in 97 (53%) of 182 samples from heparinized patients. The heparinized PTT was discordant compared with anti-Xa in 64 (35%) of 182 samples and 43 (67%) of 64 discordant samples, and 46% of concordant samples showed a prolonged prPTT. A baseline-corrected PTT reduced discordance with anti-Xa measurements by 64%.
PTT/anti-Xa discordance due to baseline PTT prolongation could be reduced using a baseline-corrected PTT.
确定肝素治疗过程中部分凝血活酶时间（PTT）基线变化与 PTT 和抗 Xa 肝素活性（anti-Xa）之间的不相符性之间的关系。
使用自动肝素中和鱼精蛋白（prPTT）测定肝素的基础 PTT。使用 prPTT 计算肝素的基础校正 PTT，以减少与抗 Xa 测量的不相符性。
prPTT 去除了高达 1 U/mL 的肝素，使正常、因子缺乏和狼疮抑制剂血浆的基础值恢复正常。在 182 份来自肝素化患者的样本中，有 97 份（53%）出现延长的 prPTT。肝素化的 PTT 与抗 Xa 在 64 份（35%）的 182 份样本中不相符，在 64 份不相符样本中，有 43 份（67%）和 46%的相符样本显示出延长的 prPTT。基础校正的 PTT 将与抗 Xa 测量的不相符性降低了 64%。
使用基础校正的 PTT 可降低因基础 PTT 延长导致的 PTT/抗 Xa 不相符性。
